What Is a Water Heater?

What Is a Water Heater?

Though a water heater performs an essential, basic task for our homes, it is a complex appliance that comes in many different styles. The classic water heater is a tank with a heating element, but increasingly, more efficient water heaters heat the water in the pipe for on-demand use. 

Let's take a look at some of the different water heating systems and show you how a Notion water sensor could save you a whole lot of stress.  


What Is a Water Heater?

A water heater heats water from the main city water supply or well and supplies it to your faucets and other appliances. Though this sounds rather simple, how a water heater works can depend on its type — from a simple tank heater to a far more complex (but more efficient) tankless system. Power sources can vary as well, from gas to electric to solar, or some combination of all of them.

How Does a Water Heater Work?

In every case, cold water enters the water heater, where it is heated up and then fed to your faucets and appliances by pipework in your home. 

The most common type of water heater in the U.S. is a tank water heater. In this case, the water passes through the main valve that supplies the tank and your home’s cold water line, and then through a shutoff valve (which you can turn off for maintenance and replacement). The water then goes through a dip tube into the bottom of the tank where it's heated by a gas or electric heating element. The hot water rises to the top of the tank and, when needed, passes out through a pipe to the faucet or appliance that needs it. 

Besides being well insulated, the hot-water tank is rounded in order to handle pressurized water inside. There will also be a pressure-relief valve to give the water somewhere to go instead of causing an explosion. By placing a Notion water sensor under the tank, if this valve leaks water, your Notion water sensor will alert you immediately so you can take action to correct the problem. At the bottom of the tank, there is a drain valve that you can use for maintenance. 

Inside the tank, there is a sacrificial anode made of a reactive metal (like aluminum or zinc) that is designed to corrode instead of the tank walls themselves. This needs replacing periodically to stop the walls of the tank from corroding. As with all appliances, regular maintenance will prolong the water heater's lifespan. 

Types of Water Heaters

Tank systems may be the most common type of water heater, but homeowners are increasingly replacing these with tankless systems. Both can run on natural gas or electricity. Other systems —  hybrid and solar heating systems, for example — are becoming more popular but are a relatively tiny proportion of those being installed today. 

Tank Water Heater (Average $1,000)

We have already described how these classic heaters work, but it's also worth noting that they aren't the most efficient option. Thanks to the cost of constantly maintaining a large, hot tank of water, they cost more money to use over time than tankless systems. However, the average cost to replace a tank water heater is generally lower than other options. They will last 10-15 years on average.

Tankless Water Heater (Average $1,375)

Here, water passes over a heating element that only switches on when an appliance or faucet requires the water. These are far more efficient than a tank system as they only heat the water you want on demand. In energy bills, you will typically save $100 a year, and a tankless water heater will usually last 20 years or more.

Replacement Costs

When it comes to the average cost to replace a water heater, HomeAdvisor estimates that a tank storage heater will cost around $1,000 to replace, plus $150–$600 in labor costs. A tankless system will cost an average of $1,375, plus $400–$1,500 in labor. Costs for hybrid or solar systems go up from there.

A Notion System Gives You Peace of Mind

Now you understand what a water heater is and how it works. But you should also consider how you can head off water heater leaks before they happen. 

Did you know that the average cost of internal water damage in the USA is $55,000, according to leading home insurers Chubb? It is far cheaper in the long run to invest in a smart home monitoring system with water leak detection — and to replace a leaking water heater as soon as you know of the problem — than to risk letting a leak go undetected causing significant damage. 


A Notion water sensor alerts your home monitoring system the second it detects water. You can place the wireless Notion Sensor directly beneath your water heater and connect it to the Notion app, which will instantly send a smartphone alert when there is a leak detected. This means you can respond immediately to the problem and save tens of thousands of dollars in damage.

In the short term, this could prevent structural damage. In the long run, it could keep you and your family from getting respiratory problems from black mold. A Notion Smart Monitoring System gives you peace of mind and could help you head off expensive repairs to your home or costly medical bills.

Learn more about how Notion Sensors can help you keep tabs on your home.